Modify HTTP headers.
Nothing leaves your machine.
HeaderLoom is a Chrome extension that adds, changes and removes request headers for API testing and debugging. No account, no analytics, no remote code, and it asks for access only to the sites you add rules for.
Coming to the Chrome Web Store Read the privacy policyFree to use. An optional one-time Pro unlock is planned; see below.
Local only
Rules are stored in Chrome's local storage on your computer. HeaderLoom sends no data anywhere.
Asks per site
No access to all websites at install. Chrome asks you when you add a rule for a site.
Built on Chrome's rule engine
Headers are changed by Chrome's declarativeNetRequest API, so the extension never reads your pages or traffic.
Bring your rules
Import a ModHeader export file and keep working with the headers you already have.
What's included
| Free | Pro (planned, $19 one-time) |
|---|---|
| Unlimited request-header rules: add, change, remove | Multiple profiles with a one-click switch |
| Pause and resume all rules | Response-header rules |
| Per-site access you approve | URL and domain filters per rule, tab-only rules |
| Import from export files | Export and import profiles as JSON, per-tab profile badge |
Pro is not on sale yet. When it is, it will be sold by a merchant of record, which will be named on this site and in the store listing together with the terms of sale and refund policy.